I am leaning towards the side of CV shaft or wheel hub problems here.. A few people have had similar problems with worn CV shafts, and i think this might be a common occurance

The integrated wheel bearing.....

Well, I just had the drivers side half axle replaced, they inspected everything on the front end, and I dont have the groanings or other symptoms of wheel hub problems. Totally at a loss, will just try the Hunter and see what happens. Tires are too new to replace.....

For those interested, this is GM'* TSB for using the Hunter GSP9700. My vibration went away when I switch away from the Goodyear RSAa.

Important:
^ Before measuring tires on equipment such as the Hunter GSP9700, the vehicle MUST be driven a minimum of 16 km (10 mi) to ensure removal of any flatspotting. Refer to Corporate Bulletin Number 03-03-10-007A or newer - Tire Characteristics of GM Original Equipment Tires.

^ Equipment such as the Hunter GSP9700 MUST be calibrated prior to measuring tire/wheel assemblies for each vehicle.

The purpose of this bulletin is to provide guidance to GM dealers when using tire force variation measurement equipment, such as the Hunter GSP9700. This type of equipment can be a valuable tool in diagnosing vehicle ride concerns. The most common ride concern involving tire radial force variation is highway speed shake on smooth roads.

Tire related smooth road highway speed shake can be caused by three things: imbalance, out of round and tire force variation. These three conditions are not necessarily related. All three conditions must be addressed.

Imbalance is normally addressed first, because it is the simpler of the three to correct. Off-vehicle, two plane dynamic wheel balancers are readily available and can accurately correct any imbalance. Balancer calibration and maintenance proper attachment of the wheel to the balancer, and proper balance weights, are all factors required for a quality balance. However, a perfectly balanced tire/wheel assembly can still be "oval shaped" and cause a vibration.

If a vibration or shake still exists after balancing, any out of round conditions, of the wheel, and force variation conditions of the tire, must be addressed. Equipment such as the Hunter GSP9700 can address both (it is also a wheel balancer).

Tire radial force vibration (RFV) can be defined as the amount of stiffness variation the tire will produce in one revolution under a constant load. Radial force variation is what the vehicle feels because the load (weight) of the vehicle is always on the tires. Although free runout of tires (not under load) is not always a good indicator of a smooth ride, it is critical that total tire/wheel assembly runout be within specification.

Equipment such as the Hunter GSP9700 loads the tire, similar to on the vehicle, and measures radial force variation of the tire/wheel assembly. Note that the wheel is affecting the tire'* RFV measurement at this point. To isolate the wheel, its runout must be measured. This can be easily done on the Hunter, without the need to set up dial indicators. If the wheel meets the runout specification, the tire'* RFV can then be addressed.

After measuring the tire/wheel assembly under load, and the wheel alone, the machine then calculates (predicts) the radial force variation of the tire. However, because this is a prediction that can include mounting inaccuracies, and the load wheel is much smaller in diameter than used in tire production, this type of service equipment should NOT be used to audit new tires. Rather, it should be used as a service diagnostic tool to minimize radial force variation of the tire/wheel assembly.

Equipment such as the Hunter GSP9700 does an excellent job of measuring wheel runout, and of finding the low point of the wheel (for runout) and the high point of the tire (for radial force variation). This allows the tire to be matched mounted to the wheel for lowest tire/wheel assembly force variation. The machine will simplify this process into easy steps.



The assembly radial force variation numbers shown should be used as a guide.

If match mounting tires to in-spec wheels produces assembly values higher than these, tire replacement may be necessary. Replacing tires at lower values will probably mean good tires are being condemned. Because tires can sometimes become temporarily flat-spotted, which will affect force variation, it is important that the vehicle be driven at least 16 km (10 mi) prior to measuring. Tire pressure must also be adjusted to the usage pressure on the vehicle'* tire placard prior to measuring.

Most GM vehicles will tolerate radial force variation up to these levels. However, some vehicles are more sensitive, and may require lower levels. Also, there are other tire parameters that equipment such as the Hunter GSP9700 cannot measure that may be a factor. In such cases, TAC should be contacted for further instructions.
Important:
^ When mounting a GM wheel to a wheel balancer/force variation machine, always use the wheel'* center pilot hole. This is the primary centering mechanism on all GM wheels; the bolt holes are secondary. Usually a back cone method to the machine should be used. For added accuracy and repeatability, a flange plate should be used to clamp the wheel onto the cone and machine. This system is offered by all balancer manufacturers in GM'* dealer program.

^ Any type of service equipment that removes tread rubber by grinding, buffing, or truing is NOT recommended, and may void the tire warranty. However, tires may have been ground by the tire company as part of their tire manufacturing process. This is a legitimate procedure.

Last time I had an "unfixable" shimmy in the front end - it turned out to be the motor mount. Just a thought...

Thanks to all for all these suggestions. It'll give me something to go to my mechanic with - I think with this many different things to look into, I have to go to someone I know I can trust to give me an honest assessment. I did confirm that I have the Goodyear RSAs as well - they are waaaaay too new to replace unfortunately, so I hope they are not the culprit. After I have him take a look, I'll post what he thinks is the solution and whether it works or not. Again, thanks for all the input though. This club is great and really helpful.

I wish one of you guys were closer, we could put a dial indicator on both the wheel & wheel mounting surface to check runout. Any of you know a machinist?

Sounds lot alot of technical, expensive, time consuming digging around and no one pointing the finger at the obvious. A simple pothole can throw your alignment out. The fact that your vibration goes away as you get up to highway speed makes me suspect that.
Also wheel weights can be a big issue and the tech that reads the balancing machine. I have had alot of times even with new tires, the shop didnt balance the tires properly and I thought the front end had serious problems.

Has anyone put on a set of Michelin tires with a 9700 balancer and a good alignment by a knowledgeable alignment guy?

The first thing that I did when I got the car was take it to a respected frame and alignment shop, had a 4 wheel alignment and all 4 tires rebalanced. It lessened it some, but it did not go away. I felt about the same way as the RSAs were virtually new on my car too but between the lousy winter traction (the main reason) and the vibration, I got rid of them and had some better, yet cheaper tires put on at a local wholesaler. The difference in ride and handling was profound...including no more vibration.

My friend'* 2000 SSEi has the Michelin Mx4 I believe, and no special balancing has been required for a vibration free ride.